)  h, 


U   S.  DEPARTMEN  I    (  >F  AGRICULTURE, 

I'.l  REAU  OF  PLANT  [ND1  STRY     Circular  No.  •-'. 

i  l.i  IW  \\     Chic    of  !*';•■ 


AN  IMPROVED  METHOD  OF  SEPARATING 

BUCKHORN  FROM  RED  CLOVER 

AND  ALFALFA  SEEDS. 


HARRY   1'..  SHAW, 
Scibntifk    Assistant,  Sugar-Beet  Investigations. 


. :■>;-,  i     in-,,  j— os 


WASHINGTON  :  GOVERNMENT  PRINTING  OFFICE  :  1908. 


BUREAU  OF  PLANT  INDUSTRY. 

Pathologist  and  Physiologist,  and  Chief  of  Bureau,  Beverly  T.  Galloway. 

Pathologist  and  Physiologist,  ami  Assistant  chief  of  Bureau,  Albert  F.  Woods. 

Laboratory  of  Plant  Pathology,  Erwin  F.  Smith,  Pathologist  in  Charge. 

Investigations  of  Diseases  of  Fruits,  Merton  B.  Waite,  Pathologist  in  Charge. 

Laboratory  of  Forest  Pathology,  Haven  Metcalf,  Pathologist  in  Charge. 

Truck  Crop  Diseases  and  Plant  Diseast    Survey,  William  A.  Orton,  Pathologist  in  Charge. 

Plant  Life  History  Investigations,  Walter  T.  Swingle,  Physiologist  in  Charge. 

Cotton  Breeding  Investigations,  Archibald  D.  Shamel  and  Daniel  N.  Shoemaker,  Physiolo- 
gists in  Charge. 

Tobacco  Investigations,  Archibald  D.  Shamel,  Wightman  W.  Garner,  and  Ernest  H. 
Mathewson,  in  Charge. 

Corn  Investigations,  Charles  P.  Hartley,  Physiologist  in  Charge. 

Alkali  and  Drought  Resistant  Plant  Breeding  Investigations,  Thomas  II.  Kearney,  Physi- 
ologist in  Charge. 

Soil  Bacteriology  ami  Water  Purification  Investigations,  Karl  F.  Kellerman,  Physiologist 
in  Charge. 

Bionomic  Investigations  of  Tropical  and  Subtropical  Plants,  Orator  F.  Cook,  Bionomist  in 
Charge. 

Drug  and  Poisonous  Plant  Investigations  and  Tea  Culture  Investigations,  Rodney  H. 
True,  Physiologist  in  Charge. 

Physical  Laboratory,  Lyman  J.  Briggs,  Thysicist  in  Charge. 

Crop  Technology  ami  Filar  Plant  Investigations,  Nathan  A.  Cobb,  Crop  Technologist  in 
Charge. 

Taxonomic  and  Range  Investigations,  Frederick  V.  Coville,  Botanist   in  Charge. 

Farm   Management  Investigations,  William  J.  Spillman,  Agriculturist  in  Charge. 

Groin  Investigations,  Mark  Alfred  Carleton,  Cerealist  in  Charge. 

Arlington  Experimental  Farm,  Lee  C.  Corbett,  Horticulturist  in  Charge. 

Vegetable   'listing  Gardens,  William   W.  Tracy,  si-.,   Superintendent. 

Sugar-Beet  Investigations,  Charles  O.  Townsend,  Pathologist  in  Charge. 

Western  Agricultural  Extension  Investigations,  Carl  S.  Scofleld,  Agriculturist  in  Charge. 

Dry-Land  Agriculture  Investigations,  E.  Channing  Chilcott,  Agriculturist  in  Charge. 

Pomological  Collections,  Gustavus  B.  Brackett,  Pomologist  in  Charge. 

Field  Investigations  m  Pomology,  William  A.  Taylor  and  G.  Harold  Powell,  Pomologists 
in  Charge. 

Experimental  Gardens  and  Grounds,  Edward  M.  Byrnes,  Superintendent. 

Fon  kiu  Seed  ami  Plant  Introduction,  David  Fairchild,  Agricultural  Explorer  in  Charge. 

Forage  Crop  Investigations,  Charles  V.  Piper.  Agrostologist  in  Charge. 

Seed  Laboratory,  Edgar  Brown,  Botanist  in  Charge. 

Grain  Standardization,  John  D.  Shanahan,  Crop  Technologist  in  Charge. 

Subtropical  Laboratory  and  Garden,  Miami,  Fla.,  Ernst  A.  Bessey,   Pathologist  in  Charge. 

Plant  Introduction   Garden,  Chico,  Cal.,  August  Mayer.  Expert   in  Charge. 

South  Texas  Garden,  Brownsville,  Tex.,  Edward  C.  Green,  Pomologist  in  Charge. 

Cotton  Culturt  farms  and  Fannies'  <  imperative  Demonstration  ~\York,  Seaman  A.  Knapp, 
Special  Agent  in  Charge. 

Seed  Distribution  (Directed  by  Chief  of  Bureau),  Lisle  Morrison,  Assistant  in  General 
Charge. 


Editor,  J.  E.  Rockwell. 
Chief  clerk,  James  E.  Jones. 


|Circ.    2] 
2 


CONTENTS. 


Introduction 5 

The  mucilaginous  property  ol  buckhorn  seeds 6 

Coating  buckhorn  seeds  after  moistening  them t> 

The  dry  sawdust  method  oi  separation 7 

Sieves  or  screens  8 

Alfalfa  or  red  clover  seeds  in  two  grades 9 

The  kind  of  Bawdusl  to  use 10 

Drj  sand  or  road-dust  method 10 

Wet  sawdust  method 11 

An  alternative  method 

ind  method 

Agglutinative  method 

Method  of  separation  uol  injurious  to  clover  and  alfalfa  seeds 12 

[CiTi 


LLUSTRATIONS. 


Page. 
Fig.  1 .  Typical  plant  of  buckhorn  ( Plantago  lanceolata  L. ) 5 

2.  Seeds  of  alfalfa  (a);  seeds  of  buckhorn  (b) 6 

3.  Alfalfa  seeds  (a);  normal  buckhorn  seeds  (b);  immature  or  abnormal 

buckhorn  seeds  (c) 7 

4.  Buckhorn  seeds  coated   with  a  grade  of  sawdust  too  coarse  to  pass 

through  a  No.  22  mesh  (a) ;  similar  seeds  coated  with  sawdust  passed 
through  a  No.  22  mesh  and  from  which  very  fine  particles  have 
been  screened  out  (6);  similar  seeds  coated  with  very  fine  sawdust 
(c);  similar  seeds  coated  with  white  sand  (d) 8 

5.  Perforated  sheet  zinc  for  sieve  to  separate  average  grade  of  red  clover 

and  alfalfa  seeds.     Holes  one-fifteenth  inch 8 

6.  Box  screen  designed  by  the  writer,  with  interchangeable  sliding  frames 

for  various  sizes  of  mesh.     Suggested  for  the  use  of  the  farmer  who 

may  raise  but  a  few  acres  of  clover  or  alfalfa 9 

7.  The  same  screen  shown  in  figure  6  with  the  frame  withdrawn  to  show 

construction 9 

8.  Mixed  sawdust  passed  through  a  No.  22  mesh   (a);  sawdust  of  same 

grade  as  a  but  with  fine  particles  (c)  sifted  out  through  a  No.  36 
mesh  (b)  (the  grade  which  should  be  used);  fine  sawdust  sifted 
from  b;  too  fine  sawdust  (c) 10 

9.  Fescue  chaff  (a);  buckhorn  seeds  coated  with  chaff  (b) 11 

10.  Small  seed  balls,  each  being  a  buckhorn  seed  to  which  alfalfa  seeds 

cling 12 

[Circ.  2] 
4 


B     !'     I 


AN 


IMPROVED  & 
BUCKHORN 
AND  A 


ETHOD  OF  SEPARATING 
FROM  RED  CLOVER 
PALFA  SEEDS.0 


INTRODUCTION. 

Many  varieties  of  weeds  are  more  or  less  commonly  found  in  clover 
and  alfalfa.  Among  these  none  is  more  common  or  more  pernicious 
than  li  ii  c  k  h  o  r  n 
I  Plantago  la  n  ■ 
lata  I.,  i .  T  li  i  s 
weed,  \\  hich  is  also 
known  as  English 
plantain,  rib-grass, 
and  ribwort,  is  a 
perennial  plant 
i  fig.  1  I  naturalized 
in  this  country 
from  Europe.  It 
fruits  freely  and 
can  not  be  eradi- 
cated by  mow  ing 
because  the  lea  \  es 
form  a  rosette  close 
to  the  ground. 

T he   seeds   of 
buckhorn    <  fig.  2, 
b)  are  of  the  same 
general  size,  shape, 
weight,  and  color  as 
those  of  red  clover 
and    alia  I  la   (fig.   •_>. 
a),    and     vary    to 
ahoiii  the  same  i  s 
tent   in  these  char 
acteristics.     For  this  reason  it  has  hitherto  been  found  impracticable 
to  separate  the  seeds  of  buckhorn  from  those  of  red  clover  and  alfalfa 


Fig.  1.  -Typical  plant  of  buckhorn  (Plantago  lanceolata  I.  I. 
From  "Farm  Weeds  in  Canada,"  issued  hy  the  Departmenl 
of   Agriculture  of  the   Dominion   of   Canada. 


i  nder  Instructions  from  Mr.  Woods,  Assistant  Chief  of  Bureau,  Mr.  Shaw 
undertook  to  work  out  a  satisfactory  method  of  separating  buckhorn  seeds  from 
[Clrc.   2] 

5 


6 


SEPARATING    BUCKHORN    FROM    CLOVER    AND    ALFALFA    SEEDS. 


■»« 

1 

/    -' 

*          # 

•••»*             % 

'% 

*           t        * 

%       0  « 

£    -%  ~ 

*•«*     %             * 

/ 

%      #     •    ' 

'     \ 

Fro.   2. — Seeds  of  alfalfa   (a)  ;  seeds  of  buckhorn   (6).      (Natural  size. \ 


by  means  of  any  of  the  methods  or  machines  in  use.  Most  other  weed 
seeds  may  be  cleaned  out  without  much  trouble,  owing  to  differences 
between  them  and  clover  seeds  in  one  or  more  particulars. 

Many  trials  were  made  in  the  Bureau  of  Plant  Industry  with  the 

best  known 
types  of 
cleaning 
machines, 
but  the y 
failed  to  ef- 
fect a  satis- 
factory sep- 
aration of 
bue  kh  orn 
seeds.  Ex- 
peri  m  e  n  t  s 
were  then 
undertaken 
to  work  out 

an  efficacious  method  that  should  be  inexpensive  and  available  alike 
to  the  farmer  and  to  the  seedsman. 

THE   MUCILAGINOUS   PROPERTY    OF    BUCKHORN    SEEDS. 

The  only  point  of  sufficiently  marked  difference  between  buckhorn 
and  clover  seeds  seemed  to  be  the  well-known  mucilaginous  character 
of  the  former.  This  mucilaginous  character  is  possessed  also  by  the 
seeds  of  peppergrass  (Lepidium  virginicum  L.)  and  false  flax  (Camt  - 
Una  sativa  Crantz).  The  mucilage  forms  a  comparatively  thick. 
glossy,  transparent,  external  coating  on  the  normal  healthy  buckhorn 
seed  and  is  very  absorbent  of  water.  When  moistened  the  seed 
becomes  much  swollen  and  very  adhesive.  A  very  small  percentage 
of  buckhorn  seeds  is  found  to  be  nonmucilaginous ;  these  are  immature 
or  abnormal  seeds  and  possess  low  vitality. 

COATING   BUCKHORN   SEEDS   AFTER   MOISTENING   THEM. 

The  idea  suggested  itself  that  after  moistening  the  seeds  and  thus 
developing  the  adhesiveness  of  the  buckhorn  seeds,  an  insoluble  sub- 
stance in  a  fine  state  of  division  might  be  mixed  with  them,  and  that 
a  portion  of  this  substance  would  adhere  to  the  buckhorn  seeds.  The 
latter  would  thus  be  increased  in  bulk,  surface  friction,  etc.,  and 
might  then  be  separated  from  the  clover  or  alfalfa  seeds  by  means 

clover.  The  results  have  been  so  satisfactory  thai  it  is  deemed  wise  to  present 
them  briefly  for  the  information  of  fanners  and  seedsmen.  An  application  for 
a  patenl  on  the  processes  described  to  permit  their  general  and  unrestricted  use 
by  the  public  has  been  filed. — B.  T.  Galloway,  Chief  of  Bureau, 

[Circ.   2] 


SEPARATING    BUCKHORN    FROM    CLOVEB     \M>    \ll\U\    SEEDS.  7 

of  one  of  the  common  types  of  seed  separators,  or  even  by  hand  sieves. 
This  proved  to  be  the  case  with  the  exception  of  a  very  small  per 
centage  "f  nonmucilaginous  bnckhorn  seeds  (fig.  3,  •  I. 


/      *  r      ' 

a  *~       I  %    \  few 


G 


Fig.  .';. — Alfalfa  seeds  (a)  ;    normal  buckhorn  s.nis  1 1,  i  :    Immature  or  abnormal  buckhorn 
eeds  (c).     i  Enlarged  three  diameters,  i 

The  methods  worked  oul  on  this  principle  arc  inexpensive,  expe- 
ditious, and  may  be  carried  nut  with  the  machines  already  in  common 
use,  or  even  with  hand  sieves,  ami  the  materials  needed  arc  likely  to 
be  accessible  t<>  every  farmer  ami  seedsman. 

THE    DRY    SAWDUST   METHOD   OF    SEPARATION. 

The  alfalfa  or  red  clover  seeds  infested  with  buckhorn  are  covered 
with  water  of  about  room  temperature  ami  well  stirred  in  order  to 
uei  all  the  seeds  thoroughly.  The  seeds  are  allowed  to  stand  in  the 
water  for  five  minutes  it'  the  latter  i-  65  \\  or  over  and  for  eight 
minutes  it'  below  thai  temperature.  The  water  i-  then  drained  oil 
thoroughly.  This  may  he  done  with  any  common  -trainer  or  sieve 
of  about  22  meshes  to  the  inch.  The  moisl  seeds  are  then  scattered 
into  dry  sawdust  and  thoroughly  mixed  until  tin'  seeds  fall  apart 
freely  and  no  -mall  seed  masses  remain.  This  mixing  may  he  done 
with  the  hand-,  with  a  rake  on  the  barn  floor,  or  with  any  suitable 
apparatus.  It  may  he  accomplished  in  two  or  three  minute-,  when 
it  will  lie  found  that  the  sawdust  ha-  absorbed  the  free  surface 
moisture  from  the  alfalfa  seeds,  ami  that  all  the  mucilaginous  buck- 
horn seeds  have  become  coated  with  the  sawdust   t  fig.  t). 

The  proportion  of  dry  seeds  to  sawdust  should  be  as  follows:  Seed-. 
one  part :  sawdust,  four  or  five  parts,  preferably  five  parts  if  resinous 
-aw dust  1"'  used. 

[Clrc.   2] 


SEPARATING    BUCKHORX    FROM    CLOVER    AND    ALFALFA    SEEDS. 


SIEVES  OK  SCREENS. 


Two  screens  are  required  to  effect  the  separation  of  buckhorn  seeds 
and  sawdust  from  alfalfa  seeds:  an  upper  one  of  sheet  zinc  perfo- 


Fig.  4. — Buckhorn  seeds  coated  with  a  grade  of  sawdust  too  coarse  to  pass  through  a  Xo. 
22  mesh  (a)  :  similar  seeds  coated  with  sawdust  passed  through  a  Xo.  22  mesh  and 
from  which  very  fine  particles  have  been  screened  out  (6)  ;  similar  seeds  coated  with 
very  fine  sawdust  (c)  :  similar  seeds  coated  with  white  sand   (d).     (Natural  size.) 

rated  with  round  holes  of  one-fifteenth-inch  diameter  (fig.  5),  and 
a  lower  one  of  No.  22  mesh  wire  cloth.  The  mixture  of  seeds  and  saw- 
dust is  fed  continuously  upon  the  upper  screen.  The  sawdust  and 
free  seeds  pass  through  to  the  lower  screen,  and  the  coated  buckhorn 
seeds  are  retained.     The  sawdust  alone  will  pass  through  the  lower 

screen,    leaving   the    clean    al- 


falfa seeds  to  lie  discharged 
by  thai  screen  into  any  suit- 
able receptacle.  Care  should 
be  taken  that  too  great  a  quan- 
tity of  the  mixture  is  not  fed 
upon  the  upper  screen  at  once. 
in  which  case  some  of  the  less 
heavily  coated  buckhorn  seeds 
may  be  thrust  through,  or  the 
sawdust  may  be  rubbed  off  and  the  buckhorn  seeds  allowed  to  escape. 
The  separation  may  be  undertaken  as  soon  as  a  thorough  mixture 
of  the  seeds  and  sawdust  has  been  effected.  The  two  screens  may  be 
used  together  in  a  light  frame  such  as  may  be  constructed  by  any 
carpenter  or  by   the    farmer  himself.     They   may   be   used   in   a   seed 

[fire.    2] 


Fig.   5. — Perforated    sheet    zinc    for    sieve    to 
separate    average    grade    of    red    clover    and 
alfalfa     seeds.         Holes     one-fifteenth     inch. 
x.'ii  ural    size  I 


SEPARATING    BUCKHORN     FROM     CLOVER    AND    ALFALFA    S] 


9 


separator,  or  in  some  such  box  as  thai  shown  in  figures  6  and  7  it' 
only  a  small  quantity  of  seeds  is  to  be  treated.  On  the  other  hand. 
the  seedsman  may 
blow  "lit  the  saw- 
dust with  a  fan 
and  separal  e  the 
buckhorn  w  i  t  h  a 
screen.  The  most 
common  t  \  pe  of 
seed  cleaner  is  a 
combination    id' 

fan   and   -ir\  es,  the 

\\  hole   separat  ion 
hid  ng  effected    i  n 

One      Operation.       ].-,,;.   r,      \-...  designed  by  the  writer,  with   Interchange- 

Should  the  t  \  i  )i  ■  ill'  :l1''''    sliding    frames    for    various   sizes   of    mesh.     Suggested 

for   the   use  of   the  farmer  who  mav   raise  l>ut    ;i   few   acres. 

machi  in1    be   em-  ,iV,t  or  alfalfa. 

ployed   that   oper- 
ates by  means  of  inclined  piano,  rebounding  angles,  and  an  oscil 
lating  motion,  the  sawdusl  should  first  be  fanned  or  sifted  out  :   then 
such  a  machine  will  effect  a  very  complete  separation  of  the  buckhorn 
seeds. 

ALFALFA   OE   RED   CLOVER    SEEDS    IN    TWO    GRADES. 

Should  the  first-mentioned  type  of  machine  or  should  hand  sieves 
be  employed   for  this  work,  it   is  advised  that  the  clover  or  alfalfa 

seeds  be  first  separated 
into  two  grades  those 
pa  -  - i  ng  t  h  fou  gh  a 
round  hole  of  one-fif- 
teenth inch  and  those 
too  large  to  pass 
through  such  a  hole. 
The  latter  grade  will 
be  found  t  o  eon  tain 
coin  pa  ra  tivel  y  few 
buckhorn  seeds  and 
will  represenl  but  a 
small  proport  ion  of 
the  total  seeds.  The 
buckhorn  should  be 
se  pa  ra  t  ed  from  the 
smaller  grade  by  the  sheet  zinc  sieve  already  mentioned,  and  from 
the  larger  grade  through  a  similar  sieve  having  holes  one-thirteenth 

[CIrc.    I'] 


Flo.  7. — 1  ii    shown    in    figure    6    with    Hi 

frame    withdrawn    to    show    construction 


10       SEPARATING    BUCKHOBN    FROM    CLOVER    AND    ALFALFA    SEEDS. 

of  an  inch  in  diameter.  If  the  seeds  are  thus  divided  into  two  grades 
very  few  clover  or  alfalfa  seeds  will  he  carried  over  with  the  1  nick- 
horn  seeds.  The  old  methods  cause  a  good  deal  of  waste  in  this 
respect. 

THE  KIND  OF  SAWDUST  TO  USE. 

Sawdust  from  any  kind  of  wood  may  he  used.  Some  of  that  used 
by  the  writer  was  mixed  sawdust  from  a  carpenter  shop  and  some 
was  from  a  planing  mill.  All  sawdust  too  coarse  to  pa<>  through 
a  Xo.  22  mesh  should  he  discarded,  a-  well  as  that  fine  enough  to  pass 
through  a  Xo.  36  mesh  (fig.  8). 


Fig.   8. — Mixed  sawdust  passed  through  a  No.   22  mesh    (a)  ;   sawdust  of  same  grade  as 
a  but  with  fine  particles    (c)    sifted  out  through  a   No.  :\C>  mesh    (6)    (the  grade  which 

should  be  used)  ;    fine  sawdust  sifted  from  h  ;    too  fine  sawdust    (c).      (Natural  size  i 

Mr.  C.  V.  Piper,  of  the  Bureau  of  Plant  Industry,  suggested  the 

use  of  the  chaff  of  various  grasses,  such  as  fescue  and  redtop.  as  being 
exceedingly  light,  absorbent,  and  of  the  proper  size.  Thi-  was  tried 
and  found  exceedingly  successful.  Whenever  available  it  may  be 
used  in  preference  to  sawdust  (fig.  9).  The  chaff  should  be  used 
in  exactly  the  same  manner  and  proportion  as  the  sawdust. 

DRY   SAND    OR   ROAD-DUST   METHOD. 

This  method  is  not  considered  quite  as  good  as  the  preceding. 
Road  dust  and  sand  are  not  nearly  as  absorbent  as  the  materials  just 
discussed;  consequently,  a  larger  proportion  of  them  must  be  used. 
say.  about  one  part  of  seeds  to  eight  of  sand  or  dust.  Furthermore, 
being  so  much  heavier  than  sawdust  or  chaff  these  materials  entail 
more  labor.  However,  the  same  method  is  applicable  to  them.  All 
sand  or  dust  too  coarse  to  pass  through  a  Xo.  36  mesh  should  be  dis- 
carded, as  well  as  that  which  is  so  fine  as  to  pass  through  a  No.  50 
mesh  (see  i\<x.  4.  d). 
[Circ.   2  1 


SEPARATING    BUCKHORN     FROM     CLOVEB     \  \  I  >     VLFALFA    - 


11 


WET   SAWDUST   METHOD. 

Use  four  parts  of  sawdust  prepared  as  described,  two  parts  of  seeds, 
and  one  part  of  water,  all  l>y  measure.  Sprinkle  the  sawdust  with 
water,  stirring  or  mixing  meanwhile  until  the  sawdust  i-  uniformly 
moistened.  An  ordinary  watering  pol  may  be  used  for  this  purpose. 
Mis    in   the  seeds   thoroughly.     Compress  the  moist   mass   with   the 


BHR 

* 

* 

:^SJEUSmbb2E9B? 

^ 

-  4 

# 

**  * 

*  4 

• 

^. 

'/It 

V     *   - 

Fig    9      Fescue  chaff   {a)  ;  buckhorn  seed     coated  with  chaff   (6).     (Natural  si 

hands  or  a  shovel  and  let  it  stand  for  aboul  fifteen  minutes  so  that 
the  buckhorn  seeds  may  have  time  to  thoroughly  absorb  moisture  and 
become  adhesive.  Then  break  up  the  mass  and  spread  out  before  a 
fan,  in  a  current  of  air,  or  in  a  seed  drier  until  quite  dry.  When 
dry.  separate  l>y  any  of  the  methods  above  described. 


AN    ALTERNATIVE   METHOD. 

Sawdust,  eight  parts;  seeds,  four  parts;  water,  three  parts.  Mix 
the  dry  seeds  and  dry  sawdust  together;  then  sprinkle  the  water  in 
and  mix  thoroughly,  a-  in  the  process  just  described.  Separate  as 
before. 

WET   SAND    METHOD. 

Proceed  exactly  as  with  the  wet  sawdusl  methods,  using  the  same 
proportions,  but  with  perhaps  rather  less  water. 

AGGLUTINATIVE   METHOD. 

Moisten  the  seeds  as  in  the  wet  sawdust  method;  drain  them  thor- 
oughly; place  them  in  a  pervious  vessel  of  any  kind.     In  these  ex 
periments  a  piece  of  perforated  sheet  zinc  was  converted  into  a  cj  lin- 

[Circ.   2] 


m 

£ 

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Fig.    10. — Small    seed   balls,    each 

being    a 

buckhorn 

seed     to1   which     alfalfa     seeds 

cling. 

i  Natural 

size,  i 

12       SEPARATING    BUCKHORN    FROM    CLOVER    AND    ALFALFA    SEEDS. 

drical  vessel.  Pack  the  seeds  into  such  a  vessel  or  into  shallow  trays 
having  wire-cloth  bottoms  of  No.  20  mesh,  or  finer.  Set  these  recep 
tacles  before  a  fan,  in  a  current  of  warm  air,  in  the  open  air  and 
sunshine,  or  in  a  seed  drier  until  the  alfalfa  seeds  fall  apart  freely 
When  moderately  dry.  screen  them  through  sieves  as  mentioned  in 
describing  the  dry  sawdust  method.  If  the  seeds  are  made  too  dry 
the  clover  will  be  too  easily  detached  from  the  buckhorn.    The  alfalfa 

seeds  will  pass  through  the 
sieves,  but  the  buckhorn 
seeds  will  be  found  to  have 
collected  about  themselves 
a  small  number  of  alfalfa 
seeds,  thus  forming  small 
seed  balls  (fig.  10),  and 
these  seed  balls  will  not 
pa  —  through  the  sieve. 

The  loss  of  good  seeds 
by  this  method  obviously 
will  depend  on  the  num- 
ber of  buckhorn  seeds  pres- 
ent, but  the  good  seeds  thus  thrown  out  may  be  saved  afterwards  by 
one  of  the  other  methods  if  desired.  This  method  is  the  simplest  and, 
aside  from  the  percentage  of  alfalfa  seeds  clinging  to  the  buckhorn 
seeds,  the  cheapest  to  operate.  Ordinarily  this  loss  will  be  from  ."i  to 
10  per  cent. 

METHOD    OF    SEPARATION    NOT    INJURIOUS    TO    CLOVER    AND 

ALFALFA  SEEDS. 

In  order  to  be  able  to  assure  the  readers  of  this  paper  that  the  red 
clover  and  alfalfa  seeds  cleaned  by  these  method-  are  not  injured, 
germination  tests  were  made  with  both  treated  and  untreated  seed-. 
No  difference  in  the  average  germinability  could  be  discovered. 

Since  the  operations  subsequent  to  the  application  of  the  sawdust, 
chaff,  etc..  are  identical  with  ordinary  seed-cleaning  processes,  other 
impurities  will  he  eliminated  at  the  same  time. 

Approved  : 

James  Wilson. 

Secretary  *</'  Agriculture. 

Washington,  I).  ('..  March  is.  1908. 

[Circ.   '.'] 


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